Conventionally, there has been a video terminal which is capable of displaying a subscreen (e.g. a 1/9-size subscreen) within a main screen, with the subscreen being arranged to display animations. In this conventional video terminal, users can select what to display on the main screen and the subscreen and where to place the subscreen on the display (specifically, wherever of four areas: top left, bottom left, top right, and bottom right) at their will.
However, no existing system permits automatic selection and switchover of screen layouts of the main screen and the subscreen.
With respect to the video conferencing system, one type of system has been recently gaining popularity, namely, a system which utilizes a multipoint control unit for connecting multiple video terminals via communication lines. The multipoint control unit (MCU) used in this video conferencing system has a continuous presence function. Where video terminals at four locations are connected together, the screen of each terminal is divided into four sections and displays images from all terminals.
While this video terminal displays a four-split composite screen, each section may further contain a subscreen, for example, in 1/9 scale. In this situation, however, the screen layout is so complicated as to spoil the total balance. Besides, when each section of the four-split composite screen includes a 1/9-size subscreen, the view of each section itself is seriously impaired. Further, as far as this four-split composite screen is concerned, one of the four sections contains a subscreen of the identical image (provided that the image is an animation). This is an inefficient screen layout.
The present invention is made in order to solve these problems. An object of the invention is to provide a video terminal, a video terminal communication system, and a video conferencing system, wherein the screen layout of the main screen and the subscreen is automatically changed and optimized through selection of the types of images to be displayed on the main screen and the subscreen.